Propeller fans with variable-pitch blades



Dec. 26, 1967 M. M. A. TROUILHET FFOPELLER FANS WITH VARIABLE-PITCH BLADES Filed Jan. 27, 1967 2 Sheets-Sheet 1 IN VENTOF? MAURICE MARIEACH/L E7Zeou/L HET 1 7 TTOP/VEVS Dec. 26, 1967 M. M. A. TROUILHET PEOPELLER FANS WITH VARIABLE-PITCH BLADES" Filed Jan. 27, 1967 25heets-Sheet 2 INVENTOR MAURICE MA #915 A CH/L L E7hou/L H57 ,4 T FQAIEVS United States Patent 3,360,051 PROPELLER FANS WITH VARIABLE-PITCH BLADES Maurice Marie Achille, Trouilhet, Lyon, France, assignor to Calor Appareils Electro-Domestiques, Lyon (Rhone), France, a company of France Filed Jan. 27, 1967, Ser. No. 612,239 Claims priority, application France, Feb. 1, 1966, 47,983 4 Claims. (Cl. 170160.43)

ABSTRACT OF THE DISCLOSURE The invention essentially relates to a propeller fan of a variable-pitch type, more particularly adapted for home use, and wherein the propeller blades are rotatively mounted on pivot pins substantially at right angles to the rotational axis to the propeller and journalled in bearings provided in the propeller-driving hub; said pivot pins are solid with stud means shifted in relation to the rotational axis of said pivot pins, said stud means engaged by a propeller-pitch controlling member presenting an annular configuration and freely sliding along the longitudinal direction of the fan-driving shaft. According to the invention the propeller fan comprises two annular members mounted and freely rotating around said fan-driving shaft located and pressed between said controlling member and the fixed frame structure of the fan, said annular members forming between them at least one cam face and being relatively rotated around the rotational axis of said propeller, a control arm member being provided and associated with at least one of said annular members.

The present invention has essentially for its object a propeller fan of the variable-pitch type, adapted more particularly for home use.

It is known that two means are available for modifying the air flow produced by a propeller fan revolving freely in the air; these means consist on the one hand in altering the propeller rotational speed, and on the other hand in modifying the blade pitch angle.

As a rule, fans for home use are driven by single-phase asynchronous electromotors of the split pole type and these motors operate satisfactorily only at a well-defined speed value; under these conditions, it is not possible to properly vary the air fiow produced by these fans by simply altering the propeller speed. Therefore, if it is desired to vary the air delivery of a fan of this type, a variable pitch propeller must be used. In this case a constructional complication arises and as a rule in known light apparatus it is not possible to modify the pitch angel of the propeller blades during the fan operation.

It is the essential object of this invention to avoid these difficulties by resorting to a very simple construction whereby, notably, the propeller blade pitch angle can be varied during the fan operation. A fan according to this invention is of the type wherein the propeller blades are rotatably mounted on pivot pins disposed substantially at right angles to the rotational axis of the propeller and journalled in bearings provided within the propeller-driving hub; these pivot pins are solid with studs or the like, which are shifted in relation to the axis of rotation of said pivot pins; said studs are driven into a translatory motion parallel to the rotational axis of the propeller and also kept in proper position by means of a propellerpitch controlling member which presents an annular configuration and slides with a certain play along the fandriving shaft. Another feature of the fan is to comprise two annular members mounted around the propeller-driving shaft, said shaft being left to rotate freely within said Patented Dec. 26, 1967 ICC annular members, these said annular members are located and pressed between said propeller-pitch controlling member and the fixed frame structure of the fan, and said annular members form between them at least one cam face and may possibly be driven into a relative rotation around the rotational axis of the propeller by means of a control arm or the like, solid with at least one of said annular members.

With this arrangement it is clear that as the fan propeller is urged against said control member by the axial pressure exerted by the air on the propeller blades, the relatively rotational position of said annular members will control the pitch angle of the propeller blade.

According to a further feature characterizing this invention, one of the aforementioned annular members is fixed in regard to the frame structure of the fan, the second being mobile according to a rotation determined by said control arm, thus allowing variations in the pitch of the propeller.

According to still a further feature characterizing this invention, the aforementioned fixed annular member comprises said cam faces forming an annular cam; the second annular member is mounted in an intermediate position between said cam and said controlling member which allows variations in the pitch of the propeller. Advantageously, a slip ring or the like is inserted between said pitch controlling member and said intermediate member. Of course, said intermediate member cannot revolve bodily with the propeller and the friction member interposed between said member and the member controlling the pitch angle will reduce to a suitable value the frictional forces tending to counteract the propeller rotation due to the axial reaction force urging the propeller against said friction member.

Advantageously, the various component elements of the variable pitch angle system, notably the hub, the blade pivot pins rigid with their studs, the control cam, etc. consist of moulded synthetic material such as notably injection-moulded thermoplastic material.

Other features and advantages of this invention will appear as the following description proceeds with reference to the accompanying drawing given by way of example and wherein;

FIGURE 1 is an axial sectional view with parts broken away showing the fan propeller and a device for controlling the pitch angle variation according to the teachings of this invention;

FIGURE 2 is a view similar to FIGURE 1 from which the various component elements of the pitch angle control system have been removed; this figure is substantially a section taken upon the line IIII of FIGURE 3;

FIGURE 3 is a sectional view of the propeller, with parts broken away and taken substantially along the line IIIIII of FIGURE 2, and

FIGURE 4 is a perspective exploded view of two component elements forming part of the propeller variable pitch-angle device illustrated in FIGURE 1.

In the specific form of embodiment illustrated in the drawing the propeller fan according to this invention comprises essentially a propeller consisting of blades 1, for example three in number, rigidly mounted on a hub 2 solid in turn with a propeller driving shaft 3. This shaft 3 is rotatably driven from a conventional electromotor (not shown). The hub 2 is rigidly assembled with the shaft 3 for example by means of a set screw 4 and a socket 5 fitting on the outer end 3a of shaft 3.

Each blade 1 is mounted on the hub 2 by means of a pivot pin 6 journalled in a bearing consisting of a pair of aligned holes 7, 8 formed in the hub 2. More particularly the holes 7 are formed in the casing 2a of hub 2 and the other holes 8 are formed in lugs 2b formed integrally 3 with the hub 2 and extending within the casing 2a parallel to the hub axis.

The pivot pins 6 are rigid with projections such as studs, fingers or the like 9 (see FIGURE 3) which are shifted in relation to the axes of rotation of said pivot pins 6 in bearings '7, 8.

The studs 9 engage fork-shaped notches 10 formed in an annular member 11 adapted to move in a direction parallel to the axis of rotation of shaft 3. This member 11 is adapted to slide with a small clearance on said shaft 3 due to its central bore 12. The member 11 of course rotates bodily with the shaft 3, hub 2 and blades 1 of the propeller.

During the propeller rotation, the air is forced in the direction of the arrow F as shown in FIGURE 1. An opposite axial reaction force is thus produced which urges the propeller and its hub backwards, this reaction force being absorbed by the shaft 3. Moreover, the variable pitch propeller blades tend to so position themselves as to minimize their drag, that is, to rotate towards a position in which they are substantially at right angles to the axis of shaft 3. Therefore, the studs 9 solid with pivot pins 6 urge the member 11 backwards in the direction of ar row 1 of FIGURE 1. This member 11 will abut against a friction member 13 consisting of a sleeve surrounding the shaft 3 with a clearance sufiicient to prevent its frictional engagement with this shaft 3. The tapered end 11a of member 11 ensures a proper centering of said sleeve 13 with respect to the axis x x of shaft 3.

The friction socket 13 engages an inner shoulder 14a of an annular member 14 shown more clearly in FIG- URE 4. In the example illustrated the member 14 has a cylindrical configuration with a bore 15 fitting with a certain play on the shaft 3 and three radial arms 16. One arm 16 is rigid with a control lever 17. These arms 16 of socket 14 engage cam faces 18 formed in a second annular member forming cam 19 rigid with the frame structure 20 of the fan. This cam member 19 comprises a central bore 21 permitting the frictionless passage of shaft 3. The cylindrical journal surface 14b of socket 14 slidably engages a bore 22 of corresponding diameter formed in cam member 19. It should be noted that the various members 13, 14 and 19 are centered in relation to the shaft axis x x by means of the cylindrical surface 23 of cam member 19 which fits exactly in the corresponding bore 24 of the fan structure 20. This structure 20 is adapted to center the cam member 19 centering in turn member 14 the latter also centering the friction socket 13 centered by the tapered end 11:: of member 11.

The apparatus is assembled as follows:

After properly mounting the propeller driving shaft 3 in the frame structure 20 of the apparatus, the parts 19, 14 and 13 are slipped thereon in succession. The various pivot pins 6 are properly positioned in the hub bearings 7 and 8, whereafter the blades 1 are secured by inserting them into the splits ends of said pivot pins 6 which are thus caused to straddle the relevant edge of the corresponding blade. These pivot pins 6 are cemented or welded on the blades. Then the blades 1 are properly inclined and each stud 9 is engaged into the corresponding form 10 of member 11, and the resulting assembly is engaged on the free end of shaft 3. Finally, the hub 2 is secured on shaft 3 by means of the set screw 4.

When the fan motor is energized it is clear that shaft 3, hub 2, blades 1 and member 11 revolve bodily and parts 14 and 19 remain stationary. The friction socket 13 may rotate or not, according to the mounting. By rotating the control lever or control arm member 117 about the axis x x the arms 16 are caused to move along the cam faces 18, thus causing the propeller-pitch controlling member 11 to recede more or less and to vary the pitch angle of blades 1 accordingly. Thus, the air delivery produced by the fan is modified as a function of the selected pitch angle.

Many modifications may be brought to the form of embodiment shown and described herein. Thus, the number of arms 16 may be modified and the cam faces 18 may be formed on member 14 instead of member 19, and on the other hand the radial arms 16 may be rigid with member 19 instead of member 14. In the example illustrated, the cam face 18 is notched, each notch corresponding to a predetermined pitch angle. As an alternative, this cam face 18 may be smooth and in this case some detent-positioning means must be provided to retain the control lever 17 in the selected pitch position.

Advantageously, the greater part or the whole of the component elements of the device described hereinabove are made of synthetic moulded material such as an injection-moulded thermoplastic material.

Of course, this invention should not be construed as being limited by the specific forms of embodiment shown and described herein which are given by way of example only and to which many modifications may be brought without departing from the scope of the invention as set forth in the appended claims.

What is claimed is:

1. A ventilator more particularly adapted for home use, of adjustable pitch propeller type comprising a fixed frame structure, a rotatable driving hub, pivot pins, adjustable pitch propeller blades rotatively mounted on said pivot pins substantially at right angles to the rotational axis of said hub, stub means shifted in relation to the rotational axis of said pivot pins, said pivot pins being solid with said stud means, a propeller pitch controlling member engaging said stud means and presenting an annular configuration and freely sliding around said hub and along the axis of said ventilator, two annular members mounted around said hub which freely rotates therein, said annular members being located and pressed between said pitch controlling member and said fixed frame structure, cam face means provided between said annular members, the first one of said annular members being fixed in regard to said frame structure, the second one being rotatively movable around the ventilator axis and a control arm member associated with said second one of said annular members, whereby on rotation of said arm member around the ventilator axis said second member rotates in respect to said first fixed member, and said cam face means are correspondingly operated imparting along said ventilator axis a longitudinal sliding motion to said second member together with said propeller pitch controlling member against which it bears for varying the pitch of the propeller blades.

2. A ventilator according to claim 1, wherein said first annular member comprises the aforementioned cam faces while said second annular member which has said control arm member associated therewith is mounted in an intermediate position between said first annular member and said propeller pitch controlling member.

3. A ventilator according to claim 2, wherein said cam faces are provided with notches.

4. A ventilator according to claim 2 including arms solid with said second annular member and wherein said cam faces are notched and are abutted against said arms, each of said arms engaging one notch of said cam face, according to the position of said control arm member.

References Cited UNITED STATES PATENTS 2,360,571 10/1944 Meehan l70160.46 2,792,897 5/1957 Dagrell l60.46 X 2,851,114 9/1958 Rossman 170160.43

EVERETTE A. POWELL, JR., Primary Examiner. 

1. A VENTILATOR MORE PARTICULARLY ADAPTED FOR HOME USE, FOR ADJUSTABLE PITCH PROPELLER TYPE COMPRISING A FIXED FRAME STRUCTURE, A ROTATABLE DRIVING HUB, PIVOT PINS, ADJUSTABLE PITCH PROPELLER BLADES ROTATIVELY MOUNTED ON SAID PIVOT PINS SUBSTANTIALLY AT RIGHT ANGLES TO THE ROTATIONAL AXIS OF SAID HUB, STUB MEANS SHIFTED IN RELATION TO THE ROTATIONAL AXIS OF SAID PIVOT PINS, SAID PIVOT PINS BEING SOLID WITH SAID STUD MEANS, A PROPELLER PITCH CONTROLLING MEMBER ENGAGING SAID STUD MEANS AND PRESENTING AN ANNULAR CONFIGURATION AND FREELY SLIDING AROUND SAID HUB AND ALONG THE AXIS OF SAID VENTILATOR, TWO ANNULAR MEMBERS MOUNTED AROUND SAID HUB WHICH FREELY ROTATES THEREIN, SAID ANNULAR MEMBERS BEING LOCATED AND PRESSED BETWEEN SAID PITCH CONTROLLING MEMBER AND SAID FIXED FRAME STRUCTURE, CAM FACE MEANS PROVIDED BETWEEN SAID ANNULAR MEMBERS, THE FIRST ONE OF SAID ANNULAR MEMBERS BEING FIXED IN REGARD TO SAID FRAME STRUCTURE, THE SECOND ONE BEING ROTATIVELY MOVABLE AROUND THE VENTILATOR AXIS AND A CONTROL ARM MEMBER ASSOCIATED WITH SAID SECOND ONE OF SAID ANNULAR MEMBERS, WHEREBY ON ROTATION OF SAID ARM MEMBER AROUND THE VENTILATOR AXIS SAID SECOND MEMBER ROTATES IN RESPECT TO SAID FIRST FIXED MEMBER, AND SAID CAM FACE MEANS ARE CORRESPONDINGLY OPERATED IMPARTING ALONG SAID VENTILATOR AXIS A LONGITUDINAL SLIDING MOTION TO SAID SECOND MEMBER TOGETHER WITH SAID PROPELLER PITCH CONTROLLING MEMBER AGAINST WHICH IT BEARS FOR VARYING THE PITCH OF THE PROPELLER BLADES. 